Abstract
Recent extensive genome studies have revealed that transposable elements occupy a large part of plant genomes. Most of these transposable elements are inactive, and they are silenced by epigenetically in some cases. Microarray analysis has shown that DDM1 of Arabidopsis thaliana participates in methylation of transposons and repetitive sequences.
In this study, we performed MSAP (methylation-sensitive amplification polymorphism) analysis to detect sequences whose DNA methylation is regulated by BrDDM1 using wild type plants and ddm1-RNAi plants with decreased DNA methylation levels. Most of sequences controlled by BrDDM1 were transposable elements and repetitive sequences. Differences of methylation states between leaves, stamens, and pistils were investigated by MSAP analysis, and sequences showing different methylation states between these organs were identified. Methylation states of these sequences in the wild type plants were as high as those in the ddm1-RNAi plants, suggesting that BrDDM1 does not contribute to differences of methylation states between organs.
